[GRASS5] Slicing tif files

[Sharyn Namnath]

Dear list,

I¹m trying to read in a greyscale georefrenced TIF file.  I have
successfully read in georeferenced color TIF files and sliced them into
smaller sections, but I am having a great deal of trouble with this
greyscale image.

First off I realized after playing with it that the greyscale required using
d.rast while the color needed d.rgb.. So far ok..

The color file was in lat/long so I read it into a lat/long location.  The
greyscale seems to be UTM, so I tried both UTM and XY locations.  Both work
for reading in and doing a d.rast and writing the file out as a PNG, but I
can¹t seem to slice the files up into smaller chunks.

When I first read in the file, I call :
r.in.gdal ­o ­e input=/Volumes/Recent/SB/p663east.tif output=temp

g.region ­p gives me :
GRASS 6.0.0 (LocationText):~ > g.region -p
projection: 0 (x,y)
zone:       0
north:      3821818.5
south:      3806127.5
west:       251135.5
east:       276337.5
nsres:      1
ewres:      1
rows:       15691
cols:       25202

d.mon start=PNG
d.rast ­o map=temp
d.mon stop=PNG

And I get a nice grainy map of my original tif file

Then I try 
g.region n=3815204.19 s=3812771.11 w=235544.84 e=238598.83

GRASS 6.0.0 (LocationText):~ > g.region -p
projection: 0 (x,y)
zone:       0
north:      3815204.19
south:      3812771.11
west:       235544.84
east:       238598.83
nsres:      0.09999918
ewres:      0.09999967
rows:       24331
cols:       30540

d.mon start=PNG
d.rast ­o map=temp
d.mon stop=PNG


And now I get a nice black image for a PNG file...

Same thing happens in the UTM location..

I¹m stumped.

Thanks for your patience...

- sharyn
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